1 files changed, 19 insertions, 9 deletions

diff --git a/drivers/scsi/scsi_transport_spi.c b/drivers/scsi/scsi_transport_spi.c
index 718a2bc4ed5e..38a53b5f9e9a 100644
--- a/drivers/scsi/scsi_transport_spi.c
+++ b/drivers/scsi/scsi_transport_spi.c
@@ -812,12 +812,10 @@ spi_dv_device_internal(struct scsi_device *sdev, u8 *buffer)
         if (!scsi_device_sync(sdev) && !scsi_device_dt(sdev))
                 return;
 
-        /* see if the device has an echo buffer.  If it does we can
-         * do the SPI pattern write tests */
-
-        len = 0;
-        if (scsi_device_dt(sdev))
-                len = spi_dv_device_get_echo_buffer(sdev, buffer);
+        /* len == -1 is the signal that we need to ascertain the
+         * presence of an echo buffer before trying to use it.  len ==
+         * 0 means we don't have an echo buffer */
+        len = -1;
 
  retry:
 
@@ -840,11 +838,23 @@ spi_dv_device_internal(struct scsi_device *sdev, u8 *buffer)
                 if (spi_min_period(starget) == 8)
                         DV_SET(pcomp_en, 1);
         }
+        /* Do the read only INQUIRY tests */
+        spi_dv_retrain(sdev, buffer, buffer + sdev->inquiry_len,
+                       spi_dv_device_compare_inquiry);
+        /* See if we actually managed to negotiate and sustain DT */
+        if (i->f->get_dt)
+                i->f->get_dt(starget);
+
+        /* see if the device has an echo buffer.  If it does we can do
+         * the SPI pattern write tests.  Because of some broken
+         * devices, we *only* try this on a device that has actually
+         * negotiated DT */
+
+        if (len == -1 && spi_dt(starget))
+                len = spi_dv_device_get_echo_buffer(sdev, buffer);
 
-        if (len == 0) {
+        if (len <= 0) {
                 starget_printk(KERN_INFO, starget, "Domain Validation skipping write tests\n");
-                spi_dv_retrain(sdev, buffer, buffer + len,
-                               spi_dv_device_compare_inquiry);
                 return;
         }